The corticosteroids are a particular type of steroids having the basic carbon skeletal formula which contains 21 carbon atoms in 4 rings, A thru D.

Corticosteroids are known to have anti-inflammatory and immunomodulatory properties useful in the treatment of numerous diseases, including autoimmune and inflammatory diseases.
A large number of 21-hydroxy-20-oxo-17-desoxy-pregnane compounds are known as therapeutically valuable substances with the action of natural corticoids, i.e. of adrenocortical hormones, or they can be used as intermediates for obtaining such active substances. These compounds have principally been obtained by removing the hydroxyl group in carbon 17. The removal of the hydroxyl group is normally carried out in several steps, usually by a direct or indirect exchange of the hydroxyl group for an hydrogen atom. Numazawa et al. (J. Chem. Soc. Chem. Commun., 1984 and Chem. Pharm. Bull., v. 34(9), pp. 3722-3726 (1986)) disclose the deoxygenation of the Dihydroxyacetone moiety at C-17 by using Iodotrimethylsilane for the preparation of Hydrocortisone, Cortisone, Prednisolone and Prednisone. German Patent NOS. 1169444 and 1211194 disclose a multistep synthesis of 17-Desoxicorticosteroids.
The processes described above suffer from various disadvantages. Therefore, there is an unmet need for an improved process for the preparation of 17-desoxy-corticosteroids in a single chemical step from commercially available starting materials.